Certain tires are usually not suitable for use in snowy road conditions and it has been the practice to put standard chains or cable chains on tires for use on snow covered surfaces. The fitting of such cables or chains is cumbersome and time consuming. An alternative is to provide specially designed snow tires which can be fitted to a vehicle for use during winter conditions but these tires need to be removed and replaced with normal tires for normal use.
Other types of traction devices are also known, such as described in U.S. Pat. No. 3,335,776 which describes an expendable traction device which comprises a band of flexible material which is fitted around the tire and bonded to the tire by means of a pressure adhesive.
In all the prior art of which the applicant is aware, the traction devices, although flexible, are not elastic or stretchable in the longitudinal direction, i.e. circumferentially of the tire around which the traction device is fitted. The applicant has found that by providing a traction device which is elastic at least in the longitudinal direction but preferably also in other directions, and which is fitted onto a tire by means of a stretch fit, provides a traction device which hugs the tire and resists becoming dislocated from the tire during use and which, on the other hand, is easily installed on a tire, without the necessity of lifting the tire from the ground surface.
The applicant has also found that it is advantageous to provide openings in the traction device which expose the tread of the tire therethrough.